1. Field of the Invention
The present invention relates to a method for successively feeding batches of constituent components into a mixing vessel for the preparation of bone cement under vacuum. The invention also relates to an apparatus for successively feeding batches of constituent components into a mixing vessel under partial vacuum for the preparation of bone cement.
2. Description of the Prior Art
Bone cement is prepared by mixing polymethyl methacrylate in powder form with liquid monomethylmethacrylate in a mixing container. Both the liquid component and the combined mixture give off substances in gaseous form which are environmentally harmful and injurious to human health. For this reason, it is important for the introduction of the bone cement components into the mixing container and the mixing process itself, to take place in such a way that the smallest possible quantity of the harmful gases escape into the surrounding environment. Mixing vessels have been developed where the introduced components were successfully prepared into bone cement without a substantial release of the aforementioned gases. However, in order for the bone cement to develop its optimal strength during use, it is also important for the components comprising the cement to have well-mixed, predetermined proportions.